Mycelial growth of Inonotus obliquus on malt extract media and on wood of different host species

Interest in the cultivation of mushrooms, including medicinal mushrooms like Chaga (Inonotus obliquus) has increased in recent years. To provide commercial cultivators with vigorous and productive strains of I. obliquus, 38 strains were isolated from the conks in Estonia and Finland. The growth rates of these isolates were determined on Malt Extract Agar (MEA), and on wood sticks of Betula pendula, B. pubescens, Alnus incana and A. glutinosa. Growth rates differed for the various isolates, depending on temperature as well as substrate. On the MEA at 9°C the fastest-growing strain of I. obliquus was PAT21061, at 18°C PAT22871 and at 22°C PAT21058. On B. pendula, the I. obliquus strain, PATKJ180 had the highest growth rate; on B. pubescens, PAT21061; on A. glutinosa, PATKA880; and on A. incana, PATKA2679 exhibited the highest growth rate. But the growth rate characteristics of I. obliquus were not correlated with the host species origin of the fungus isolate. Still, the ability of strains to form conks is unknown and needs to be tested in vivo. Because I. obliquus grows faster in Betula wood than Alnus, the use of Betula wood for producing inoculation dowels is recommended in order to shorten the production time.